Expandable-Volume Liner for a Collapsible Liquid Holding Tank

ABSTRACT

An expandable-volume liner is usable with a collapsible liquid holding tank frame consisting of top and bottom rails spaced apart by vertical struts. The expandable-volume liner has pliant impervious side walls, a pliant impervious floor panel and at least one pliant impervious collapsible bag extending outwardly from the liner. Each bag is optionally extendable between its respective surrounding top and bottom rails and adjacent struts to conform the tank to the differing footprints presented by various sites and the volume of liquid necessary to accomplish the task at hand. The liners are especially suited to firefighting applications and can be used in conjunction with existing frames built for non-expandable volume liners.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/113,202 which was filed Feb. 6, 2015.

BACKGROUND OF THE INVENTION

This invention relates generally to collapsible portable tanks for storing liquids and more particularly concerns the pliant, impermeable liners used with such tanks.

Portable tanks for storing liquids typically consist of a frame of rigid top and bottom rails spaced by rigid vertical struts. The corners of the tank and the midpoints of two opposite top and bottom rails are hinged. The opposed hinged rails can be V-folded toward the center of the tank until the other rails come together in parallel. My earlier U.S. Pat. No. 8,746,478 describes one type of collapsible tank frame in detail, noting that such tanks are usually about 30″ high, from 6′ to 18′ on each side and capable of holding from 500 to 5,000 gallons of water.

Whatever the size of the tank and the nature of the collapsible hardware, the frame generally unfolds into a predetermined and invariable square or rectangular footprint. More recently, frames have been designed with multiple hinges in opposite side rails allowing the same frame to be unfolded into one of two such footprints.

The tanks are often necessary in firefighting scenarios in which water is not readily accessible at the site. In practice, the folded tank is stored on, and transported by, a fire truck dispatched to the site of the fire. On site, the tank frame is unloaded, unfolded and filled with water carried by a tanker truck to the site. The tanker truck may be the transporting fire truck. As the water is being exhausted from the tank by the firefighters, the tanker truck travels to and from a water supply station to refill the tank.

Folded tanks are usually stored on the rack of a transporting fire truck and, in common practice, only one tank is stored on the truck. The possibility of storing multiple tanks on the same truck is an expensive, space eating and deployment-time increasing luxury rarely used in firefighting applications. But the tank to be used in a given application must take into account the demands of the fire and the distance from the deployed tank to a remote water supply for refilling the tank. So two competing criteria, volume and footprint, have a major impact on the decision as to the size of the tank to be stored on the transporting truck. On one hand, in order to accommodate a wider range of possible storage capacity requirements, a larger tank is preferred. On the other hand, because of unique site features, such as irregular terrain or immovable obstacles, the largest site footprint available may be quite restricted. Therefore, in order to accommodate a wider range of footprint alternatives, a smaller tank is preferred.

It is, therefore, an object of the invention to provide a liquid storing collapsible portable tank having a footprint changeable to comply with a footprint presented by the site at which the tank will be used. And it is a further object of this invention to provide a liquid storing collapsible portable tank of expandable maximum volume.

SUMMARY OF THE INVENTION

In accordance with the invention, a liner is provided for a collapsible, portable, liquid holding tank frame having top and bottom rails spaced apart by vertical struts. The liner has pliant impervious side walls and a pliant impervious floor panel. At least one opening through the pliant impervious side walls is sized to be surrounded by the top and bottom rails and two adjacent struts of the frame. At least one pliant impervious collapsible bag, one for each opening, has a mouth welded to its corresponding opening. Each bag is extendable from its mouth between its respective surrounding top and bottom rails and adjacent struts and outwardly from the side walls to its closed end. Each mouth has at least one strap connectable at one of its ends to the top or bottom rail and at its other end to the bottom or top rail, respectively. Each strap extends between its corresponding adjacent struts so that its corresponding bag, when folded from its closed end to its mouth into a stored condition, can be secured in the stored condition by its at least one strap.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:

FIG. 1 is a top perspective view of a preferred embodiment of an empty liner mounted on a collapsible liquid holding tank with three of four expandable bags extended from the liner;

FIG. 2 is a side perspective view of the empty expandable liner of FIG. 1 mounted on the collapsible liquid holding tank with the three of four expandable bags extended from the liner;

FIGS. 3A and 3B are a side elevation view of the empty expandable liner of FIG. 1 mounted on the collapsible liquid holding tank with the three of four expandable bags extended from the liner;

FIG. 4 is a top plan view of the empty expandable liner of FIG. 1 mounted on the collapsible liquid holding tank, including a plurality of hand grips used to facilitate manipulation of the expandable liner;

FIGS. 5A and 5B are a side elevation view of the expandable liner of FIG. 1 mounted on the collapsible liquid holding tank with the liner and the three extended expandable bags filled with liquid; and

FIG. 6 is a side perspective view of the expandable liner of FIG. 1 mounted on the collapsible liquid holding tank with the liner and the three extended expandable bags filled with liquid.

While the invention will be described in connection with a preferred embodiment thereof, it will be understood that it is not intended to limit the invention to that embodiment or to the details of the construction or arrangement of parts illustrated in the accompanying drawings.

DETAILED DESCRIPTION

Looking at FIGS. 1-4, a collapsible, portable, liquid-holding tank frame 10 is seen in an empty condition. The frame 10 shown has top and bottom rails 11 and 13 spaced apart by vertical struts 15 and hinged at the four corners and midpoints of two opposite sides of the frame 10. The frame 10 supports a liner 20 formed by pliant, impervious side walls 21 and a pliant, impervious floor panel 23. As shown, the upper edges of the sidewalls 21 are fitted with grommets 25 and are secured by lacing 27 to the top rails 11.

At least one opening, and as shown four openings 29, are provided through the liner side walls 21. Each opening 29 is surrounded by two proximal adjacent struts 15 of the frame 10 and the portions of the top and bottom rails 11 and 13 of the frame 10 lying between its two proximal adjacent struts 15. As shown, each of the four top and bottom rails 11 and 13 of the tank frame 10 are spaced by six struts 15, so each side wall 21 appears in five side wall segments. However, any number of struts 15 at any desired spacing could be used.

For the tank shown, at least one of the segments is adapted to provide a drain passage 17 for evacuation of liquid from the liner 20 after use. Thus, the liner 20 shown has nineteen wall segments, five in each of three side walls 21 and four in the other side wall 21, through which openings 29 could be provided. However, in the illustrated application, only four of the segments have openings 29. As best seen in FIG. 5A, when the liner 20 is filled with liquid, the drain passage 17 will have been folded over the top rail 11 and secured to the inside face of its side wall 21.

Returning to FIGS. 1-4, at least one pliant, impervious, collapsible bag 30 is provided, one for each opening 29 through the side walls 21. The mouth 31 of each bag 30 is welded or otherwise sealed along its perimeter to the perimeter of its corresponding opening 29 through the side walls 21. As shown, each bag 30 can be independently and optionally extended from its mouth 31 outwardly from its respective liner side wall 21.

Continuing to look at FIGS. 1-4, for storage, each bag 30 can be, and one of the bags 30 has been, folded from its closed end 33 to its mouth 31. The folded bag 30 may then be secured in the folded condition against the tank side wall by straps 35 or other types of fasteners. At least one and, as shown two, straps 35 can be used between the corresponding adjacent struts 15 of their respective bags 30. As best seen in FIG. 1, the lower end of each strap 35 is connectable to the bottom rail 13 or to the tank liner 20 proximate the bottom rail 13, as shown by wrapping the lower end of the strap 35 around the lower rail 13 and fastening it to itself with hook-and-loop fasteners 37. The strap 35 is then extendable upwardly across the folded bag 30 and over top rail 11 and connectable at its upper end to the inside of the tank wall 21 between the corresponding adjacent struts 15, perhaps by snaps, buckles or, as shown, mating segments of hook-and-loop material 39. The straps 35 may be narrow, as shown, or wide enough to extend fully across their respective bags 30 in the stored condition. The four segments having openings are preferably, and as shown, in hinged mid-point walls 21 of the tank so that, when the tank is collapsed, the folded bags 30 are interior to the collapsed liner 20.

Returning to FIGS. 1-4, in deploying a tank on a site, the tank frame 10 is oriented on the site in a manner which will permit the liner floor panel 23 and any bags 30 intended to be extended from the tank to lie within the site footprint. The frame 10 and liner 20 are unfolded and secured in their orthogonal use configuration. The straps 35 or other mechanisms used to secure the bags 30 in the stored condition are then disconnected and the bags 30 extended outwardly from the tank between their respective vertical struts 15. Any number of bags 30 suited to the site footprint and needed for increased tank volume can be extended. For the embodiment as shown, the tank includes and extends four bags 30.

Turning now to FIGS. 5 and 6, the deployed tank has been filled with liquid which, for many applications and particularly for firefighting applications, will be water W. The liner 20 and the extended bags 30 will be simultaneously filled with water W as the liquid level rises in the tank. Thus, the collapsible bags 30 increase the storage capacity of the tank while simultaneously allowing the liner 20 to fit within the standard frame dimensions for the desired size of tank. For example, by extending one 500 gallon bag 30 from an otherwise 2,000 gallon liner 20 associated with a 2,000 gallon frame 10, a tank capacity of 2,500 gallons of water W is possible using the 2,000 gallon frame 10. The extension of two bags 30 would afford a tank capacity of 3,000 gallons of water W using the same frame 10.

Looking at FIG. 4, grips 19 are shown fixed to the floor panel 23 of the liner 20 for use in manipulating the liner 20 to aid in discharging the liquid from the liner 20 and/or to collapse the tank after use. Similarly, one or more grips 19 may also be fixed to the collapsible bags 30 to aid in discharging liquid from the extended bags 30 and/or to fold the extended bags 30 after use.

The increase in storage capacity without any corresponding increase in frame size minimizes the costs and the deployment time, and simplifies the transportation and storage, of the tank. Furthermore, a collapsible bag liner 20 can be deployed in an existing standard-liner frame, thereby increasing storage capacity while totally eliminating the cost of acquiring a new frame. And, by selection of appropriate bags 30 for extension, the footprint of the expanded volume tank can be tailored to suit the footprint presented by the site.

Thus, it is apparent that there has been provided, in accordance with the invention, an expandable-volume liner for a collapsible liquid holding tank has been provided that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with a specific embodiment thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims. 

What is claimed is:
 1. For lining an interior of a collapsible, portable, liquid holding tank frame having top and bottom rails spaced apart by vertical struts, a liner comprising: pliant impervious side walls and a pliant impervious floor panel, said pliant impervious side walls having at least one opening therethrough sized to be surrounded by the top and bottom rails and two adjacent struts of the frame; and at least one pliant impervious collapsible bag, one for each said opening, having a mouth welded to its corresponding said opening, said bag being extendable from said mouth between its respective surrounding said top and bottom rails and adjacent struts and outwardly from said side walls.
 2. A liner according to claim 1, each said mouth having at least one strap connectable at one end to one of said top and bottom rails and at another end to another of said top and bottom rails between its corresponding adjacent struts whereby said bag, when folded from a closed end thereof to its mouth into a stored condition, can be secured in said stored condition by said at least one strap. 